Comparison of 18 F-florbetaben quantification results using the standard Centiloid, MR-based, and MR-less CapAIBL ® approaches: Validation against histopathology.

Introduction: ¹⁸ F-florbetaben is currently approved for the visual rule out of β-amyloid (Aβ) pathology. It is also used for recruitment and as an outcome measure in therapeutic trials, requiring accurate and reproducible quantification of Aβ burden in the brain.
Methods: Data from eighty-eight subjects (52 male subjects, aged 79.8 ± 10.6 years) who underwent antemortem ¹⁸ F-florbetaben positron emission tomography scan and magnetic resonance imaging less than a year before neuropathological assessment at autopsy were evaluated. Image analysis was performed using the standard Centiloid (CL) statistical parametric mapping approach and CapAIBL ^® . Imaging results were compared against autopsy data.
Results: Against combined Bielschowsky silver staining and immunohistochemistry histopathological scores, statistical parametric mapping had 96% sensitivity, 96% specificity, and 95% accuracy, whereas magnetic resonance-less CapAIBL standardized uptake value ratio _{Whole Cerebellum} had 94% sensitivity, 96% specificity, and 95% accuracy. Based on the combined histopathological scores, a CL threshold band of 19 ± 7 CL was determined.
Discussion: Quantification of ¹⁸ F-florbetaben positron emission tomography scans using magnetic resonance-based and magnetic resonance-less CapAIBL ^® approaches showed high agreement, establishing a pathology-based threshold in CL.
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